Pharmaceutical for improving dysphagia

ABSTRACT

A dysphagia improving composition characterized in that a substance having an inhibitory action on an angiotensin converting enzyme, which is a degrading enzyme of substance P, is administered locally in a dosage not influencing blood pressure, and a pharmaceutical for improving dysphagia containing the composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application of PCT/JP2013/066340, filed Jun. 13, 2013.

TECHNICAL FIELD

The present invention relates to a pharmaceutical composition for improvement of dysphagia and prevention of aspiration pneumonia.

BACKGROUND ART

In the case of dysphagia, swallowing becomes difficult in eating and drinking, and a patient is often forced to give up eating and drinking through the mouth, nutrition intake, which raises a great problem from the viewpoint of QOL. At the same time, mental and physical stress on a caregiver who cares for eating and drinking becomes very heavy. Further, the percentage of pneumonia in causes of death in the elderly increases sharply, and a most part thereof is believed to be aspiration pneumonia caused by dysphagia.

Onset of dysphagia is frequently caused by disorder of basal ganglia derived from cerebral vascular disorder, Parkinson's disease, aging, excessive administration of an antipsychotic drug, or the like. By reduced activity of the nigrostriatal dopaminergic neurons in the site, synthesis of substance P, which is up-regulated by dopaminergic neurons, is decreased. When the synthesized substance P is released from a nerve terminal of the vagal nerve and the glossopharyngeal nerve sensory branch, a swallowing reflex is elicited. Therefore, decrease in the amount of substance P decreases a swallowing reflex to trigger aspiration, and especially when intraoral bacteria enter into the lung by inapparent aspiration, they can cause aspiration pneumonia. Consequently, improvement of a swallowing reflex in eating and drinking is quite important for a person inconvenienced by dysphagia to improve their QOL, and for caregiver to reduce the burden, as well as to prevent aspiration pneumonia.

Conventionally, as a treatment method for dysphagia, rehabilitation has been practiced. However, the rehabilitation requires sometimes unreasonable endeavor of a relevant person, and is applicable not to all symptoms. As a treatment using a drug or the like, the following Non-Patent Literature and Patent Literature report as a conventional example that capsaicin, a pungent component, promotes release of substance P from a nerve terminal and improves swallowing reflex (Patent Literature 1), but also report that continuously use of capsaicin induces depletion of substance P. Further, it is suggested that a preparation used for a treatment of Parkinson's disease, such as levodopa and amantadine, improves dysphagia by acting on dopaminergic neurons in the nigrostriatum (Non-Patent Literature 1), but due to side effects administration must be done cautiously. Meanwhile, an angiotensin converting enzyme participates in degradation of angiotensin I as well as substance P as substrates, and therefore it is inferred that by administration of an angiotensin converting enzyme inhibitor degradation of substance P is suppressed and dysphagia can be improved, and further it is reported that onset of pneumonia can be suppressed (Non-Patent Literature 1). However, in order to inhibit the action of an angiotensin converting enzyme by oral administration, an angiotensin converting enzyme inhibitor is used in the same dosage as that used as an antihypertensive agent, and therefore care needs to be taken in using the inhibitor, because the inhibitor decreases the blood pressure of a person with a normal blood pressure or even with a low blood pressure. Especially in the case of an aged person, excessive reduction of the blood pressure may have various negative influences, such as dizziness, lightheadedness, sleeplessness, and fatigue, as well as decrease in an intracerebral blood flow amount. Further, when an angiotensin converting enzyme inhibitor is administered orally, even at a dosage as an antihypertensive agent, improvement of dysphagia is observed only after long term administration for a few weeks or longer, and a fast-acting effect has not been recognized.

CITATION LIST Patent Literature

-   Patent Literature 1: JP Patent Publication (Kokai) No. 2004-300103A

Non Patent Literature

-   Non Patent Literature 1: Ohrui Takashi, Status Quo of Aspiration     Pneumonia in Elderly and Countermeasures, Proceedings of the 52nd     academic meeting of Japanese Geriatrics Society, Japanese Journal of     Geriatrics, (2010) 47: 558-560

SUMMARY OF INVENTION Technical Problem

As described above, past compositions or treatments for prevention of aspiration pneumonia and improvement of dysphagia have inevitably side effects. Therefore, the first object of the present inventors is to develop a pharmaceutical for prevention of aspiration pneumonia and improvement of dysphagia with little side effect. The second object is to develop a pharmaceutical containing an agent having an inhibitory action on an angiotensin converting enzyme as an active ingredient, to be applied by a specific administration method for prevention of aspiration pneumonia and improvement of dysphagia without causing a side effect such as blood pressure reduction. Further, the third object is to develop a pharmaceutical containing an agent having an inhibitory action on an angiotensin converting enzyme as an active ingredient, with which by a specific administration method an improving effect on dysphagia can be seen soon after the administration, though by oral administration the improving effect on dysphagia soon after the administration cannot be expected.

Solution to Problem

Under such circumstances, the present inventors conducted diverse investigations and found that by administering a substance having an inhibitory action on an angiotensin converting enzyme directly to a pharyngeal part a strong improving effect on dysphagia can be obtained without exhibiting a blood-pressure-lowering effect.

A pharmaceutical for improving dysphagia according to the present invention completed based on the above knowledge contains a component having an inhibitory action on an angiotensin converting enzyme to be administered locally to a pharyngeal site as an active ingredient.

A drug for improving dysphagia according to the invention of the present application includes a therapeutic drug for dysphagia, and a preventive agent for dysphagia.

Advantageous Effects of Invention

The present invention provides a pharmaceutical composition, by which improvement of dysphagia and prevention of aspiration pneumonia can be expected by using a substance having an inhibitory action on an angiotensin converting enzyme with an administration method and/or a dose, which do not influence the blood pressure. Further, the invention of the present application can improve dysphagia at a time point when oral administration cannot yet develop an effect, namely instantaneously.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing the results of a study of a swallowing reflex decreasing effect by multiple administrations of haloperidol in Experimental Example 1.

FIG. 2 is a graph showing the results of a study of a swallowing reflex improving effect by local administration to a pharyngeal site of a captopril aqueous solution in a guinea pig dysphagia model received multiple administrations of haloperidol in Example 1.

FIG. 3 is a graph showing the results of a study of a swallowing reflex improving effect by local administration to a pharyngeal site of a lisinopril aqueous solution in a guinea pig dysphagia model received multiple administrations of haloperidol in Example 2.

FIG. 4 is a graph showing the results of a study of decrease in a swallowing reflex in a normal guinea pig by local administration to a pharyngeal site of a substance P receptor antagonist, and an improving effect by a prior local administration to the pharyngeal site of a captopril aqueous solution in Example 3.

FIG. 5 is a graph showing the results of a study of an effect of local administration to a pharyngeal site of a substance P receptor antagonist on a swallowing reflex improving effect by local administration to a pharyngeal site of a lisinopril aqueous solution in guinea pigs dysphagia model received multiple administrations of haloperidol in Example 4.

FIG. 6 is a graph showing the results of a study of swallowing reflex improving effects by local administration to a pharyngeal site and oral systemic administration of a captopril aqueous solution after 30 min of the administration in guinea pigs dysphagia model received multiple administrations of haloperidol in Comparative Example 1.

FIG. 7 is a graph showing the results of a study of swallowing reflex improving effects by local administration to a pharyngeal site and oral systemic administration of a lisinopril aqueous solution after 120 min of the administration in a dysphagia model received multiple administrations of haloperidol in Comparative Example 2.

FIG. 8 is a graph showing the results of a study of an influence of a prior administration of a captopril aqueous solution or a lisinopril aqueous solution on blood pressure increase by intravenous administration of angiotensin I in a normal rat in Comparative Example 3.

DESCRIPTION OF EMBODIMENTS

1. Dysphagia Improving Drug: Substance Having an Inhibitory Action on an Angiotensin Converting Enzyme

A substance having an inhibitory action on an angiotensin converting enzyme is an inhibitory substance of an enzyme converting angiotensin I to angiotensin II, and used in general for a treatment of hypertension. An angiotensin converting enzyme has low substrate selectivity and degrades also substance P as a substrate. By administration of a substance having an inhibitory action on an angiotensin converting enzyme for inhibiting degradation of substance P, the concentration of the substance P in the body is increased, and dysphagia can be improved.

Typical examples of a substance having an inhibitory action on an angiotensin converting enzyme herein include captopril, lisinopril, enalapril, benazepril, imidapril, alacepril, perindopril, quinapril, temocapril, trandolapril, cilazapril, and delapril as well as active metabolites thereof.

2. Mode of Administration and Administration Route

With a dysphagia improving drug containing a substance having an inhibitory action on an angiotensin converting enzyme as an active ingredient according to the invention, the active ingredient can be administered locally. More specifically, a dysphagia improving drug according to the invention includes a dysphagia improving drug, which locally administers a substance having an inhibitory action on an angiotensin converting enzyme as an active ingredient to at least one site selected from an intraoral site, a pharyngeal site, a laryngeal site and the respiratory tract. By local administration to at least one site selected from a pharyngeal site, a laryngeal site and the respiratory tract as above, dysphagia can be improved instantaneously by a substance having an inhibitory action on an angiotensin converting enzyme without exhibiting a blood-pressure-lowering effect, thereby preventing aspiration pneumonia.

More favorably, a dysphagia improving drug according to the invention includes a dysphagia improving drug, which locally administers a substance having an inhibitory action on an angiotensin converting enzyme as an active ingredient to a pharyngeal site. The local administration can be made, for example, in a mode by which the drug is directly applied to the pharyngeal mucosa.

3. Dosage Form

A dysphagia improving drug according to the invention is applied in a form to be absorbed by the intraoral mucosa, the pharyngolaryngeal mucosa, and the respiratory tract mucosa. More specifically, it may be in the form of a spray, a film preparation, an oral/endolaryngeal patch, a nebulizer, a liquid for direct application or the like, containing a substance having an inhibitory action on an angiotensin converting enzyme as an active ingredient.

-   (1) Examples of an edible and water-soluble film base to be used for     a film preparation or an oral/endolaryngeal patch include gelatin,     pectin, arabinoxylan, sodium alginate, carrageenan, xanthan gum,     guar gum, pullulan, hypromellose, hydroxypropyl cellulose,     water-soluble hydroxyethyl cellulose, methyl cellulose,     carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone,     and polyethylene glycol. -   (2) As a carrier to be used for an inhalant (nebulizer) or a spray,     a saccharide, a sugar alcohol, an amino acid and/or an inorganic     salt can be used. Examples of a saccharide include milk sugar, grape     sugar, cane sugar, maltose, trehalose, maltodextrin, and dextran.     Examples of a sugar alcohol include mannitol, xylitol, erythritol,     maltitol, sorbitol, arabitol, and xylose. Examples of an amino acid     include leucine, isoleucine, lysine, valine, threonine, methionine,     cysteine, cystine, phenyl alanine, tryptophan, and glycine. Examples     of an inorganic salt include calcium carbonate, sodium chloride, and     calcium phosphate. Milk sugar may be used favorably. -   (3) To a liquid for direct application, an emulsifier, a suspending     agent, or a preservative may be added as needed. Examples of an     emulsifier include polysorbate 80, lauromacrogol, glyceryl     monostearate, sodium lauryl sulfate, and lecithin. Examples of a     suspending agent include polyvinyl alcohol, povidone, carmellose     sodium, methyl cellulose, hydroxypropyl cellulose, hydroxymethyl     cellulose, sodium alginate, and gum arabic.     4. Administration Target

A dysphagia improving drug according to the invention may be administered to a dysphagia patient, and an aged person, a patient with cerebral vascular disorder, a Parkinson's disease patient, and a person taking an antipsychotic drug, who are susceptible to dysphagia.

Since spraying, nebulizing, or direct application is an administration method not demanding a swallowing work of saliva, it can be applied irrespective of the degree of swallowing function disorder. Therefore, administration by spraying, nebulizing, or direct application is preferable in the case of severe dysphagia.

5. Timing and Frequency of Administrations

A dysphagia improving drug according to the invention may be administered locally in a single dose to a pharyngeal site, a laryngeal site and/or the respiratory tract. In the case in which a drug is used daily by multiple administrations or repeated administrations, a single local administration means the first administration, and a dysphagia improving effect can be obtained by each administration. In this regard, according to the invention, dysphagia can be improved within a period, in which an oral administration does not yet develop an effect. Namely, since the drug is fast-acting, an angiotensin converting enzyme inhibitory component may be directly applied to the pharyngeal mucosa preferably before each meal and/or at bedtime, and more preferably 30 min in advance of the above.

6. Dosage

Each dose should be an amount, which does not cause decrease in blood pressure, and improves dysphagia. An amount substantially less than an amount necessary for decreasing the blood pressure can improve dysphagia. More specifically, each dose is less than the lowest dose, with which blood pressure decreasing activity can be expected, preferably 1/10 thereof, and more preferably 1/100 thereof. For example, in the case of lisinopril, each dose is less than the lowest dose (2.5 mg), with which blood pressure decreasing activity can be expected when administered to a human, preferably 1/10 thereof i.e. 250 μg, and more preferably 25 μg, and the same can be reduced to 1 μg according to the following Examples. Namely, in the case of lisinopril, which has relatively high inhibitory activity among substances having an inhibitory action on angiotensin used in Examples, a dose based on body weight converted from a dysphagia improvement effective dose obtained in Examples is 5 ng/kg, and for a human having an average body weight of 60 kg a dysphagia improving effect can be obtained by an administration of each 300 ng or more.

The invention will now be described in more detail by way of Examples, etc., provided that the following description should not be considered to limit the scope of the invention in any way.

It has been known as described above, that dysphagia derived from basal ganglia disorder may appear due to administration of an antipsychotic drug, such as haloperidol, which suppresses the action of dopaminergic neurons. Therefore the inventors constructed an animal model of swallowing function disorder induced by repeated overdosage of haloperidol, and evaluated the drug efficacy.

EXPERIMENTAL EXAMPLE 1

To 6 week-old female Hartley guinea pigs (330 to 390 g) habituated for 1 week after receipt, a physiological saline solution, or a haloperidol solution was injected subcutaneously in a dosage of 1 mg/kg approx. every 12 hours twice per day for 7 days. Thereafter, a guinea pig was fixed at extremities, and 500 μL of distilled water was injected over 5 sec through a device to a part just before the pharynx, and the total frequency of swallowing until 10 sec and 30 sec from the injection was measured based on a muscle movement in a pharyngeal site. Thereafter a physiological saline solution, or a haloperidol solution was injected again (1 mg/kg).

[Result]

The measurements were repeated totally 4 times at intervals of 1 min. The results are shown in FIG. 1. As obvious from FIG. 1, water drinking frequency in the group received repeated administrations of haloperidol is significantly decreased compared to the guinea pig group received repeated administrations of a physiological saline solution. Based on the result, the guinea pig was used as a dysphagia model induced by repeated administrations of haloperidol in the following experiments for evaluation of drug efficacy.

EXAMPLE 1 Effect of Captopril Local Administration

In the same way as in Experimental Example 1, 1 mg/kg of a haloperidol solution was administered repeatedly to 6-week old Hartley female guinea pigs (330 to 390 g), and on day 8 water drinking reflection was measured as above, which was defined as an initial value. On day 2 of the initial value measurement, 100 μL of distilled water, or an aqueous solution with 50 mM, 50 μM, or 50 nM of captopril (pH 7.0) was sprayed with a spray device directly in a single dose to the pharyngeal mucosa of a guinea pig. Water drinking reflection was measured 30 min after the spray in the same way as in the initial value measurement (measured value).

The results are shown in FIG. 2. As obvious from FIG. 2, there was no significant change in the water drinking frequency in the group sprayed with distilled water, but significant increase in the water drinking frequency was observed in the groups sprayed with aqueous solutions containing 50 mM or 50 μM of captopril.

EXAMPLE 2 Effect of Lisinopril Local Administration

A guinea pig dysphagia model induced by repeated administrations of haloperidol was prepared in the same way as in Example 1, and 100 μL of a 0.5 nM to 500 μM aqueous solution of lisinopril (pH 7.0) was sprayed with a spray device directly in a single dose to the pharyngeal mucosa of a guinea pig, followed by measurement of the influence on water drinking reflection.

The results are shown in FIG. 3. As obvious from FIG. 3, there was no significant change in water drinking frequency in the group sprayed with distilled water, but dose-dependent increase in water drinking frequency was observed in the groups sprayed with a lisinopril aqueous solution, and at a dose of 50 nM or more there was significant increase in water drinking frequency in the same way as in the group sprayed with a 50 μM aqueous solution of captopril.

EXAMPLE 3 Involvement of Substance P, Prevention of Dysphagia

FK888 (10 μM, 50 μL/guinea pig), which is a substance P receptor antagonist, was administered locally with a spray device to a pharyngeal site of a guinea pig, and water drinking reflection frequency was measured in the same way as in Experiment 1.

The results are shown in FIG. 4. As obvious from FIG. 4, decrease in swallowing reflex by single local administration to a pharyngeal site of FK888 was observed. Further, in the case, in which an aqueous solution of captopril was administered locally in a single dose 30 min before the administration of FK888 with a spray device to a pharyngeal site in the same way as in Example 1, decrease in swallowing reflex by the FK888 administration was suppressed.

EXAMPLE 4 Involvement of Substance P, Mechanism of Dysphagia Improving Effect

A guinea pig dysphagia model induced by repeated administrations of haloperidol was prepared, and 100 μL of a 50 nM aqueous solution of lisinopril was sprayed with a spray device directly in a single dose to the pharyngeal mucosa. Thereafter, 10 nM, 100 μL of FK888 as a substance P receptor antagonist, which is the lower limit not influencing swallowing reflex, was administered locally with a spray device to the pharyngeal mucosa, and water drinking frequency was measured in the same way as in Experimental Example 1.

The results are shown in FIG. 5. As obvious from FIG. 5, increase in water drinking frequency observed 30 min after the administration of 100 μL of a 50 nM aqueous solution of lisinopril was almost completely suppressed by the administration of FK888 (10 nM, 100 μL) 15 min after the lisinopril administration.

COMPARATIVE EXAMPLE 1 Advantage of Captopril Local Administration

With respect to the dysphagia improving effect by a substance having an inhibitory action on an angiotensin converting enzyme, an oral administration (p.o., intragastric administration) and a local administration with a spray device to the pharyngeal mucosa (s.i.) were compared in terms of change in water drinking frequency. A guinea pig dysphagia model induced by repeated administrations of haloperidol was prepared in the same way as in Example 1, and 100 μL of a 50 μM aqueous solution of captopril, or a 50 mM aqueous solution of captopril was administered locally in a single dose with a spray device to the pharyngeal mucosa, or the same dose of captopril was administered orally (intragastric administration). The water drinking frequency was measured 30 min after the administration.

The results are shown in FIG. 6. As obvious from FIG. 6, a single local administration of either of the 50 μM captopril aqueous solution and the 50 mM captopril aqueous solution in an amount of 100 μL, exhibited an improving effect on dysphagia within a short time of 30 min from the administration, however an oral administration of either of the dosages did not exert an influence.

COMPARATIVE EXAMPLE 2 Advantage of Lisinopril Local Administration

With respect to the dysphagia improving effect by lisinopril, an oral administration (p.o., intragastric administration) and a local administration to the pharyngeal mucosa (s.i.) were compared in terms of change in water drinking frequency in the same way as in Comparative Example 1. A guinea pig dysphagia model induced by repeated administrations of haloperidol was prepared, and 100 μL of a 50 mM lisinopril aqueous solution was administered locally with a spray device to the pharyngeal mucosa, or the same dose of lisinopril was administered orally (intragastric administration). The water drinking frequency was measured 2 hours after the administration (when the blood drug concentration after an oral administration reaches a maximum).

The results are shown in FIG. 7. As obvious from FIG. 7, a local administration of 100 μL of the 50 μM lisinopril aqueous solution exhibited an improving effect on dysphagia even 2 hours after the administration, but an oral administration exerted no influence.

COMPARATIVE EXAMPLE 3 Effect on Blood Pressure Increase Induced by Angiotensin I

Influence of a dose of a 50 μM aqueous solution of captopril in an amount of 100 μL, or a 5 μM aqueous solution of lisinopril in an amount of 100 μL, which exhibited improvement of dysphagia in Example 1 and Example 2, on blood pressure was analyzed using SD male rats (350 to 400 g). The respective dose of a captopril, or lisinopril aqueous solution was administered orally and the blood pressures were measured after 1 hour. Thereafter, angiotensin I was administered intravenously (300 ng/kg) to induce blood pressure increase and a change in the mean blood pressure was measured.

The results are shown in FIG. 8. As obvious from FIG. 8, administration of 100 μL of the 50 mM aqueous solution of captopril, or 100 μL of the 5 mM aqueous solution of lisinopril suppressed a vasopressor reaction by administration of angiotensin I, but administration of 100 μL of the 50 μM aqueous solution of captopril, or 100 μL of the 5 μM aqueous solution of lisinopril had no influence.

It has been known that overdosage of haloperidol induces also in a human clinical case decrease in an amount of substance P in blood and also decrease in swallowing reflex. Therefore it was so considered that a guinea pig dysphagia model induced by repeated administrations of haloperidol used according to the invention reflected the human clinical status.

From Example 1, Example 2, and Comparative Example 3 it became clear that decrease in swallowing reflex could be improved by single local administration of a substance having an inhibitory action on an angiotensin converting enzyme to a pharyngeal site at a dose not affecting the blood pressure.

From Example 3 it could be so understood that a single local administration of a substance having an inhibitory action on an angiotensin converting enzyme to a pharyngeal site could suppress prophylactically dysphagia to be caused by a substance P receptor antagonist by suppressing degradation of substance P in pharyngeal tissues. In addition, from Example 4 it could be so understood that a single local administration of a substance having an inhibitory action on an angiotensin converting enzyme to a pharyngeal site could improve disorder in a guinea pig dysphagia model induced by repeated administrations of haloperidol by suppressing degradation of substance P in pharyngeal tissues so as to enhance swallowing reflex elicited by substance P.

It was so judged from Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 that by single local administration of a substance having an inhibitory action on an angiotensin converting enzyme, not only improvement of dysphagia at a low dose, which does not affect the blood pressure, can be achieved, but also an early improving effect on dysphagia, which cannot be obtained by an oral administration, can be obtained. The dose of 100 μL of a 50 mM captopril aqueous solution in Comparative Example 1 is a dose exhibiting an advantageous blood-pressure-lowering effect in various animal models. The dose of 100 μL of a 50 mM lisinopril aqueous solution in Comparative Example 2 is almost equivalent to a human clinical dose based on the body weight as a therapeutic drug for hypertension, and is a dose exhibiting adequate blood-pressure-lowering effect in a human and an animal, but no dysphagia improving effect was observed by an oral administration even at a time point when the blood drug concentration was maximum. It was then judged that oral administration of a dose used for a human clinical treatment of hypertension could not obtain an early improving effect on dysphagia as in the case of a local administration. From the above it has been concluded that a single local administration of a substance having an inhibitory action on an angiotensin converting enzyme to a pharyngeal site is a superior application method to provide a dysphagia improving drug, which does not induce depletion of substance P from a nerve terminal, not cause various side effects such as blood pressure decrease as in the case of an oral administration of a dopamine preparation or a substance having an inhibitory action on an angiotensin converting enzyme, and can exhibit drug efficacy early after administration.

All the publications, patents, and patent applications cited herein are incorporated herein in their entirety by reference. 

The invention claimed is:
 1. A method for treating a subject suffering from dysphagia or aspiration pneumonia, comprising administering a dysphagia improving drug for local administration, comprising lisinopril as a sole active ingredient, for local administration at a dosage to a pharyngolaryngeal site, wherein the drug is administered by spraying, nebulizing, or direct application, wherein the dosage treats dysphagia without lowering blood pressure, and is less than 2.5 mg but more than 300 ng.
 2. The method of claim 1, wherein the drug treats dysphagia within a shorter period compared to that observed with oral administration of the drug. 